Solar collector panel arrangements of the type just mentioned are, for example, described in German Patent Publication No. 3,615,264. Dividing the solar cell surface into two symmetrically arranged solar generator wings has proven itself in practical terms in the past and is used frequently. Comparing the fully folded state of the solar generator wings on the one hand with the fully unfolded state of the wings on the other hand, it is noted that the center of gravity of the solar generator and thus of the spacecraft such as a satellite, is substantially unchanged in both circumstances. The kinematic elements for the folding and unfolding, including the enforced control of the folding and unfolding, are known, for example, as a CCL.
In certain flight phases it may be sufficient to supply the spacecraft with a reduced solar power. For this purpose it is customary that only one wing is unfolded or that only a few outer panels near the panel wing tips of both solar generator wings are partially unfolded. Such a state of operation is shown, for example, in FIG. 1 of the above mentioned German Patent Publication (DE-OS) No. 3,615,264. It is clear that the one-sided position of a partially unfolded panel leads to a noticeable displacement of the center of gravity of the solar generator and thus of the satellite. The satellites have, as a rule, a rocket drive, also referred to as apogee motor or engine, for the purpose of reaching the intended orbit after separation from the last rocket stage. The axis of the apogee motor extends normally through the center of gravity of the spacecraft or satellite, whereby the center of gravity is determined or given by the folded or fully unfolded condition of the solar generator wings. If the apogee motor is switched on for an acceleration while the solar generator wings are partially unfolded, a torque moment is generated due to the mentioned displacement of the center of gravity. Such torque moment may, for example, be a yawing moment about the axis of the solar generator. Such a moment must be sensed by the position control system of the spacecraft so that it can be compensated. The compensation may, for example, be accomplished by tilting the apogee motor, by switching-on auxiliary engines, by causing a mass displacement, or by producing other counter moments, for example, with the aid of a gyro. However, all these measures increase the requirements that must be met by the position closed loop control system. As a result, such a system becomes more complicated, more expensive, and heavier. The more complicated system is also subject to a larger probability of failure. Incidentally, the above German Patent Publication corresponds to U.S. Pat. No. 4,747,566 (Kiendl).